Operator&#39;s key for telephone-switchboards.



No. 824,843. PATENTED JULY 3, 1906. .W. M. BROWN. OPERATORS KEY FOR TELEPHONE SWITGHBOARDS.

A PPLIUATION FILED JUNE 26,1901.

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- with either subscriber for any necessary purcame STATES PATENT omen WILLIAM MILTON BROWN, OF JOHNSTOWN, PENNSYLVANIA, ASSIGNOR OF ONE-FOURTH TO GEORGE H. PARMELEE, OF JOHNSTOWN, PENN- SYLVANIA.

Specification of Letters Patent.

ratenteq July 3, 1906.

Application filed June 26, 1901. Serial No 66.094.

2'0 all whmn it may concern:

Be it known that 1, WILLIAM MILTON BROWN, of J ohnstown, in the county of Cambria and State of Pennsylvania, have invented a new and useful Improvement in Operators Keys for Telephone-Switchboards, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part of this specification.

My invention relates to operators keys for telephone-switchboards, and is designed to provide a simple form of key capable of application to existing types of switchboards and whereby the operator may ring up or communicate with either of two connected subscribers, but is absolutely prevented from listening-in and overhearing the conversation between the subscribers-that is to say, the operator may communicate at will with either subscriber for any necessary purpose, but is prevented from listening to their conversationthus insuring on single lines absolute privacy to the subscribers.

With this object in view my invention consists in a key so constructed and arranged in the circuits that when in its normal position it forms a part of the circuit between two connected subscribers and entirely exchides the operators instruments, and al though by a proper movement of the key such instruments may be connected at will pose such operation if attempted for the purpose of listening-in will at once break the subscribers connection and interrupt their conversation.

My invention also consists in certain novel features in connection with the ringing devices of the key and also in the novel construction, combination, and arrangement of parts, all as hereinafter described, and pointed out in the appended claims.

The main feature of my invention, as above stated, is susceptible of various embodiments but the particular embodiment herein shown and described I find to be a very simple and satisfactory one and constitutes the preferred construction.

In the accompanying drawings, Figure 1 l is a central vertical section of an operators 1 and shown in two parts in order to show clearly both the front and back contacts. In this view the key is shown in full lines in position for communicating with one of the subscribers, shown in full lines in position for connecting the operators instruments with one of the subscribers, and in dotted lines in position for ringing up the other subscriber.

In the figures the numeral 1 designates the frame of the device.

2 is a lever, of insulating material, pivoted in the frame at 3 and having a handle portion 2*, which projects up through an oblong slot 4 in the top of the frame.

5 indicates dust-guard plates, which are secured to the lever and close the slot 4.

Secured to one side of an insulating-block 6 at the base of the lever are two flexible contact-strips 7 and 8, which extend up at one side of the lever, and similarly secured and arranged at the opposite side of the lever are two other similar flexible contact-strips 9 and 10. The two strips '7 and 9 will be referred to herein as the front contact-strips, while the strips 8 and 10 will be referred to as the back contact-strips. On the body of the lever are two contacts 11 and 12, having laterally-projecting pins or studs, as shown, for engagement with the adjacent front and back contact-strips. The contact 11 in the normal position of the lever (shown in Fig. 1) electrically connects the front contacts 7 and 9, while the contact 12 similarly connects the back contacts 8 and 10. These front and back contact-strips also act as springs tending to hold the lever in the normal central position. (Shown in Fig. 1.)

Secured to an insulating-block 13, supported on the frame adjacent to the contactstrips 7 and 8 and designed to be engaged, re-

spectively, thereby are two fixed contacts 14 and 15, and secured to a similar block 13" adjacent to the strips 9 and 10 are two similar contacts 16 and 17. The connection of the various contacts in the circuit will be described presently in connection with Fig. 5.

Mounted to reciprocate vertically in the interior of the key-lever is a plunger 18, having a projecting finger-cap or button 19. Secured to this plunger is a cone-shaped cam piece 20, which when the plunger is depressed passes wedge-like between two flexible spring-strips 21 22, secured to the lever, and. spreads them laterally into engagement with the respective contacts 11 and 12 in a manner which will be readily apparent from an inspection of Fig. 2. The strips 21 and 22 are pivotally secured to the metallic supports 23, which carry the pivots of the key lever and lie in slots or recesses 24 in the sides of said lever. When the lever is in its central position, as shown in Fig, 1, the plunger 18 cannot be depressed, for the reason that its lower end will impinge against the base-block 25; but when the lever is moved in one direction to the position shown in dotted lines in Fig. 5 or in the other direction to the position shown in Fig. 3 the lower end of the plunger, if the latter be pressed, will enter one of the two recesses 27in said base block, and thereby permit the cam-piece or spreader 20 a sufficient downward movement to cause it to operate the contactstrips 21 and 22 in the manner above described. The recesses 27 are so located. that the plunger will enter them just before the key-lever is moved over sufficiently far to cause the engagement of the contact-strips 7 and 8 or 9 and. 10 with the contacts 14 and 15 or 16 and 17, but not until the lever has been moved far enough to break the connection between the contacts 7 and 8 and. the contacts 9 and 10.

18' is a spring for returning the plunger to its normal position as soon as it is released.

I will now describe the diagram. shown in Fig. 5 and then explain the operation of the key. In this diagram, A designates the usual.

telephone instruments of one subscriber, and.

B the similar instruments of a second subscriber. C designates the operators instruments, (receiver and transmitter.) G is the generator, D the drop for subscriber A, and E the drop for subscriber B. F is the clearing-out drop, and H and I the usual plugs for establishing the subscribers con nections by insertion in the spring-jacks H and I. The two poles of the generator G are connected, respectively, to the strips 21 and 22 by the conductors 31 and 32. The four contacts 14, 15, 16, and 17 are connected in multiple with the conductor 33, in which are included the operators instruments. The front contact-strip 7 is connected to the sleeve of the plug H, the back strip 8 to the tip of the plug H through the conductor 34 and the clearing-out drop. The front strip 9 is connected to the tip of the plug I through the conductor 35, and the back strip 10 is connected to the sleeve of the plug I.

The manner of using the key is as follows: Suppose the subscriber, whose instruments are indicated at A, (and who is referred to herein as subscriber A,) signals the operator at central in the usual manner. The opera tor answers his call by inserting the plug H in the jack H and throws the key-lever over to the left a sufficient distance to cause the contacts 7 and 8 to engage the contacts 14 and 15. The circuit is now complete from the operators phone O, as follows: to contacts 14 and 7, to sleeve of plug H through the instruments of subscriber A to jack H, tip of the plug H, conductor 34, and contacts 8 and 15 back to C. The operator may therefore talk with subscrib er A and having ascertained from him the connection which he desires (which will be assumed to be subscriber B) the operator next inserts the plug I in the jack I and moves the key-lever to the right to the dotted position shown in Fig. 5, pressing meanwhile on the cap or button 19 of the plunger 18 until the lower end of the latter enters one of the recesses 27. The circuit is now from one pole of the generator G through conductor 31, to contact-strip 21, to contacts 11 and 9, conductor 35, tip of the plug I to signal of subscriber B, back to the sleeve of the plug I, to contacts 22 and 10, and thence to the other pole of the generator, thus completing a ringing-circuit with subscriber B. It will be noted that when this ringing-circuit is completed the position is such that both the operators instruments and the lines of subscriber A are excluded from the circuit. Having given the signal to subscriber B, the operator releases the keylever, which (under the influence of the contacts 9 and 10 acting as springs) returns to its normal central posi'tion, where it forms the connection between the front and back strips. There is now a complete talking-circuit between the two subscribers, as follows: over the instruments of subscriber A to the tip of the plug H, thence to back contact-strip 8, to contact 12, to back contact-strip 10, to sleeve of the plug I, to the instruments of subscriber B, back to tip of the plug I, to front contactstrip 9, contact 11, to front contact-strip 7, to sleeve of plug H, to subscriber A. In case the subscriber B should be the calling subscriber the operation is precisely the same as that just described, except that the key is thrown in the opposite direction for the purpose of connecting in the operators instruments to ascertain the subscribers wishes s gsas and is also moved in the opposite direction to ring up a subscriber. It will not be necessary to trace the circuits in this case, for they are readily apparent from the diagram.

It will be noted that the operators instruments are entirely excluded from the talkingnone of the front and back contact-strips are in engagement with any of the fixed contacts with which thesaid instruments are connected and that while the operator may, by throwing the lever to one side or the other, readily communicate with either of the subscribers for any desired purpose by so doing she will at once break the circuit between the subscribers and interrupt the conversation. It will also be seen that the general form of my improved key is such that it may be readily applied to the ordinary types of switchboards now in use.

The invention is clearly applicable to systems in which ground is used for one side of the lines. I would also state that it is by no means necessary to my invention that the particular devices which I have herein shown and described for the ringing-circuits be employed, as various means, such as a separate button or key, may be employed for this purpose without affecting the main invention. I prefer, however, to employ the combined key which I have herein shown and described. As above indicated, I also do not wish to limit myself to the particular construction and arrangement of the contact-carrying devices and contacts which I have herein shown and described, as these may be otherwise con structed and arranged to secure the main obj ects of my invention without departing from its spirit and scope.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. An operators key for telephone-switchboards, having a movable contact-carrying member through which in its normal position a talking-circuit between two connected subscribers is effected, and stationary contacts to which the operators instruments are connected, said member being movable to connect the operators instruments with either of the subscribers and thereby make impossible a simultaneous connection between the subscribers.

2. An operators key for telephone-switchboards, provided with fixed and movable contacts to which the operators and the subscribers instruments may be respectively connected and means for making such connections, the movable contacts having one position relatively to the fixed contacts in which two subscribers may be directly connected with each other and the operators instruments excluded, and two other positions in each of which the operators instruments are connected with one subscriber to the exclusion of the other the contacts and connections being arranged to positively prevent the simultaneous connection of the operators instruments with both subscribers. circuit between the two subscribers, S1I1C 3. An operators key for telephone-switchboards, having one set of contacts to which the lines of one subscriber may be connected, a second set to which the lines of a'second subscriber may be connected, and other contacts to which the operators instruments are connected, in combination with a movable device which in its normal position forms a connection between the said sets of contacts and is disconnected from these contacts to which the operators instruments are connected,

. and which by movement operates to connect the operators instruments with either one of two subscribers and in such positions make impossible a connection between subscribers.

4. An operators key for telephone-switchboards, having fixed and movable contacts and means for connecting said contacts with the lines of two subscribers and the operators instruments, said contacts being arranged relatively to each other to connect the subscribers in a talking-circuit only at such times as the operators"ins'truments are entirely excluded, and also to connect said instruments with either subscriber only at such times as the other subscriber is excluded.

5. An operators key for telephone-switchboards, having one set of contacts to which the lines of a subscriber may be connected, a second set to which the lines of another subscriber may be connected, and a third set for connection with the operators instruments, and means whereby any two of said. contact sets, but no more, can be included at the same time in a talking-circuit.

6. An operators key for telephone-switchboards, consisting of contacts to which the .lines of two subscribers and the operators instruments may be connected and nears for making such connections, and a movable member forming in its normal position. a working connection between the contacts of the subscribers lines, and which is operative to connect either one of said lines, but not both simultaneously, with the operators instruments.

7. An operators key for telephcne-switch boards, having fixed contacts, connected in multiple with the, operators instruments, movable contact-pieces adjacent to but normally separated from the fixed contacts, and to which the lines of two subscribers may be connected, a movable member which in its normal position electrically connects the said movable contact-pieces and thereby two subscribers in a talking-circuit, and which may be moved to either side of its normal position to engage one set of said movable contacts and force them into engagement with the adjacent fixed contacts.

8. An operators key for telephoneswitchboards, consisting of a set of movable contacts to which the lines of a subscriber may be connected, a second set of movable contacts to which the lines of a second subscriber may be connected, fixed contacts adjacent to each of the movable contacts to which the operators instruments are connected, and a movable contact'device which in its normal position connects the two sets of movable contacts and which is movable in one direction to actuate one set of the movable contacts to engage them with the adjacent set of fixed contacts, and similarly movable in the opposite direction to cause the engagement of the other set of movable and fixed contacts, said device forming the only means of completing a connection between the two subscribers and also between each subscriber and the operator.

9. In an operators key for telephoneswitchbcards, the combination of two sets of fixed contacts to which the operators instruments are connected in multiple, movable contacts adjacent to each of the fixed contacts and normally separated therefrom, and a movable contact device located be tween the movable contacts and normally held by them in a position to electrically eonnect them, said device having a lateral movement in two directions to break its engagement with one set of movable contacts and at the same time force the other set of movable contacts into engagement with the adjacent fixed contacts.

10. An operators key for telephoneswitchboards, consisting of two sets of fixed contacts connected in multiple with the operators instruments, flexible contact-strips adjacent to each of the fixed contacts and normally separated therefrom, said strips forming terminals to which the lines of two subscribers may be connected in the usual manner, and a contact-carrying lever pivoted between said strips and electrically connecting the same when in its normal position, said lever having a lateral movement .in each of two opposite directions to cause the engagement of each set of said strips withthe adjacent fixed contacts.

11. An operators key for telephoneswitchboards, consisting of two sets of fixed contacts connected in multiple with the operators instruments, a set of movable contacts adjacent to each set of the fixed contacts and forming terminals to which the lines of two subscribers may be connected in the usual manner, a lever pivoted between and normally connecting the two sets of movable contacts, contacts on said lever salsa connected to the opposite poles of a source of electric energy, means on said lever for engaging said contacts with either set of the movable contacts, and means for preventing said engagementexcept when said lever is at certain predetermined positions.

12. An operators key for telephoneswitchboards, consisting essentially of two sets of fixed contacts connected in multiple with. the operators instruments, two sets of movable contacts, one set adjacent to each set of fixed contacts, and arranged to be moved into engagement with the same, said movable contacts forming terminals to which the lines of two subscribers may be connected in the usual manner, a lever pivoted between the two sets of movable contacts and normally connecting said sets electrically,

said lever being movable to break the said connection and at the same time force one set of movable contacts into engagement with its adjacent fixed contacts, two insulated contacts on said lever connected to the poles of a generator, and a button or plunger carried by the lever and arranged to engage the last-named contacts to spread the same laterally, and means for preventing the operation of said button or plunger except when said lever is in certain predetermined positions.

13. In an operators key for telephoneswitchboards, the combination with contacts for connection with the subscribers and operators instruments, of a lever arranged to engage said contacts to connect either one of two subscribers in circuit with the operators instruments and also to conmeet both subscribers together with the operators instruments excluded, of a pair of separated spring-contacts carried by said lever and connected with the poles of a current generator or supply, and a push-button or plunger mounted on said lever and arranged ,by depression thereof to move and further separate said springcontacts, together with means for preventingthe depression ofsaid button or plunger except at such times as the lever is in a position to effect neither of the connections above specified.

14. In an operators key for telephoneswitchboards, the combination with contacts to which the subscribers and operators instruments are connected, of a lever arranged to electrically connect said contacts in several predetermined ways, spring-com tacts on said lever, a reciprocating plunger also carried by said lever and extending through the lower end thereof into contact with the frame of the key, and a cam on said plunger for engaging said contacts, said frame being recessed to permit movement of said plunger when the lever is in certain predetermined positions.

15. In an operators key for telephonej ble contacts forming terminals for subscribswitchboards, a pivoted key-lever, flexible ers lines, and the fixed contacts terminals to spring-contacts bearing against opposite which the operators instruments are consides of said lever and normally holding it in nected in multiple.

5 central position, means on said lever for elec- In testimony whereof I have afiixed my I 5 trio-ally connecting said contacts when the signature in presence of tWo Witnesses. lever is in a central position, and fixed con, WVILLIAM MILTON BROWN. tacts adjacent to each of the flexible conl/Vitnesses: tacts and with which the latter may be en- CORA G. Cox,

:0 gaged by a movement of the lever, said fiexi- H. W. SMITH. 

